LONDON - Oil giant BP faced a new furor yesterday as it confirmed that it had lobbied the British government to conclude a prisoner-transfer agreement that the Libyan government wanted to secure the release of the only person convicted for the 1988 Lockerbie airliner bombing over Scotland, which killed 270 people, most of them Americans.

The acknowledgment came after U.S. lawmakers, grappling with the company's Gulf of Mexico oil spill, called for an investigation into BP's actions in the case of the freed man, Abdel Basset Ali al-Megrahi.

Al-Megrahi, an ex-Libyan intelligence agent, was released and allowed to return to Libya in August after doctors told the Scottish government that he was likely to die of advanced prostate cancer within three months. But nearly a year later, he remains alive and free.

BP's statement yesterday repeated earlier acknowledgments that it had promoted the transfer agreement to protect a $900 million offshore oil-and-gas exploration deal off Libya's coast. The British justice minister at the time, Jack Straw, admitted shortly after al-Megrahi was freed that the BP deal was considered in the government's review of his case.